Re: [PATCH v8 04/15] x86: Secure Launch Resource Table header file

ross.philipson
2024-02-22T17:50:54Z

On 2/15/24 12:08 AM, Ard Biesheuvel wrote:
> On Wed, 14 Feb 2024 at 23:31, Ross Philipson <ross.philipson@oracle.com> wrote:
>>
>> Introduce the Secure Launch Resource Table which forms the formal
>> interface between the pre and post launch code.
>>
>> Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
>> ---
>> include/linux/slr_table.h | 270 ++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 270 insertions(+)
>> create mode 100644 include/linux/slr_table.h
>>
>> diff --git a/include/linux/slr_table.h b/include/linux/slr_table.h
>> new file mode 100644
>> index 000000000000..42020988233a
>> --- /dev/null
>> +++ b/include/linux/slr_table.h
>> @@ -0,0 +1,270 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Secure Launch Resource Table
>> + *
>> + * Copyright (c) 2023, Oracle and/or its affiliates.
>> + */
>> +
>> +#ifndef _LINUX_SLR_TABLE_H
>> +#define _LINUX_SLR_TABLE_H
>> +
>> +/* Put this in efi.h if it becomes a standard */
>> +#define SLR_TABLE_GUID EFI_GUID(0x877a9b2a, 0x0385, 0x45d1, 0xa0, 0x34, 0x9d, 0xac, 0x9c, 0x9e, 0x56, 0x5f)
>> +
>> +/* SLR table header values */
>> +#define SLR_TABLE_MAGIC 0x4452544d
>> +#define SLR_TABLE_REVISION 1
>> +
>> +/* Current revisions for the policy and UEFI config */
>> +#define SLR_POLICY_REVISION 1
>> +#define SLR_UEFI_CONFIG_REVISION 1
>> +
>> +/* SLR defined architectures */
>> +#define SLR_INTEL_TXT 1
>> +#define SLR_AMD_SKINIT 2
>> +
>> +/* SLR defined bootloaders */
>> +#define SLR_BOOTLOADER_INVALID 0
>> +#define SLR_BOOTLOADER_GRUB 1
>> +
>> +/* Log formats */
>> +#define SLR_DRTM_TPM12_LOG 1
>> +#define SLR_DRTM_TPM20_LOG 2
>> +
>> +/* DRTM Policy Entry Flags */
>> +#define SLR_POLICY_FLAG_MEASURED 0x1
>> +#define SLR_POLICY_IMPLICIT_SIZE 0x2
>> +
>> +/* Array Lengths */
>> +#define TPM_EVENT_INFO_LENGTH 32
>> +#define TXT_VARIABLE_MTRRS_LENGTH 32
>> +
>> +/* Tags */
>> +#define SLR_ENTRY_INVALID 0x0000
>> +#define SLR_ENTRY_DL_INFO 0x0001
>> +#define SLR_ENTRY_LOG_INFO 0x0002
>> +#define SLR_ENTRY_ENTRY_POLICY 0x0003
>> +#define SLR_ENTRY_INTEL_INFO 0x0004
>> +#define SLR_ENTRY_AMD_INFO 0x0005
>> +#define SLR_ENTRY_ARM_INFO 0x0006
>> +#define SLR_ENTRY_UEFI_INFO 0x0007
>> +#define SLR_ENTRY_UEFI_CONFIG 0x0008
>> +#define SLR_ENTRY_END 0xffff
>> +
>> +/* Entity Types */
>> +#define SLR_ET_UNSPECIFIED 0x0000
>> +#define SLR_ET_SLRT 0x0001
>> +#define SLR_ET_BOOT_PARAMS 0x0002
>> +#define SLR_ET_SETUP_DATA 0x0003
>> +#define SLR_ET_CMDLINE 0x0004
>> +#define SLR_ET_UEFI_MEMMAP 0x0005
>> +#define SLR_ET_RAMDISK 0x0006
>> +#define SLR_ET_TXT_OS2MLE 0x0010
>> +#define SLR_ET_UNUSED 0xffff
>> +
>> +#ifndef __ASSEMBLY__
>> +
>> +/*
>> + * Primary SLR Table Header
>> + */
>> +struct slr_table {
>> + u32 magic;
>> + u16 revision;
>> + u16 architecture;
>> + u32 size;
>> + u32 max_size;
>> + /* entries[] */
>> +} __packed;
>
> Packing this struct has no effect on the layout so better drop the
> __packed here. If this table is part of a structure that can appear
> misaligned in memory, better to pack the outer struct or deal with it
> there in another way.
>
>> +
>> +/*
>> + * Common SLRT Table Header
>> + */
>> +struct slr_entry_hdr {
>> + u16 tag;
>> + u16 size;
>> +} __packed;
>
> Same here
>
>> +
>> +/*
>> + * Boot loader context
>> + */
>> +struct slr_bl_context {
>> + u16 bootloader;
>> + u16 reserved;
>> + u64 context;
>> +} __packed;
>> +
>> +/*
>> + * DRTM Dynamic Launch Configuration
>> + */
>> +struct slr_entry_dl_info {
>> + struct slr_entry_hdr hdr;
>> + struct slr_bl_context bl_context;
>> + u64 dl_handler;
>
> I noticed in the EFI patch that this is actually
>
> void (*dl_handler)(struct slr_bl_context *bl_context);
>
> so better declare it as such.
>
>> + u64 dce_base;
>> + u32 dce_size;
>> + u64 dlme_entry;
>> +} __packed;
>> +
>> +/*
>> + * TPM Log Information
>> + */
>> +struct slr_entry_log_info {
>> + struct slr_entry_hdr hdr;
>> + u16 format;
>> + u16 reserved;
>> + u64 addr;
>> + u32 size;
>> +} __packed;
>> +
>> +/*
>> + * DRTM Measurement Policy
>> + */
>> +struct slr_entry_policy {
>> + struct slr_entry_hdr hdr;
>> + u16 revision;
>> + u16 nr_entries;
>> + /* policy_entries[] */
>
> Please use a flex array here:
>
> struct slr_policy_entry policy_entries[];

Yes we will use flex arrays everywhere it is relevant in here going forward.

Thanks
Ross

>
>> +} __packed;
>> +
>> +/*
>> + * DRTM Measurement Entry
>> + */
>> +struct slr_policy_entry {
>> + u16 pcr;
>> + u16 entity_type;
>> + u16 flags;
>> + u16 reserved;
>> + u64 entity;
>> + u64 size;
>> + char evt_info[TPM_EVENT_INFO_LENGTH];
>> +} __packed;
>> +
>> +/*
>> + * Secure Launch defined MTRR saving structures
>> + */
>> +struct slr_txt_mtrr_pair {
>> + u64 mtrr_physbase;
>> + u64 mtrr_physmask;
>> +} __packed;
>> +
>> +struct slr_txt_mtrr_state {
>> + u64 default_mem_type;
>> + u64 mtrr_vcnt;
>> + struct slr_txt_mtrr_pair mtrr_pair[TXT_VARIABLE_MTRRS_LENGTH];
>> +} __packed;
>> +
>> +/*
>> + * Intel TXT Info table
>> + */
>> +struct slr_entry_intel_info {
>> + struct slr_entry_hdr hdr;
>> + u64 saved_misc_enable_msr;
>> + struct slr_txt_mtrr_state saved_bsp_mtrrs;
>> +} __packed;
>> +
>> +/*
>> + * AMD SKINIT Info table
>> + */
>> +struct slr_entry_amd_info {
>> + struct slr_entry_hdr hdr;
>> +} __packed;
>> +
>> +/*
>> + * ARM DRTM Info table
>> + */
>> +struct slr_entry_arm_info {
>> + struct slr_entry_hdr hdr;
>> +} __packed;
>> +
>
> These two look preliminary, so better to drop them now and introduce
> only once you know what they will look like.
>
>> +struct slr_entry_uefi_config {
>> + struct slr_entry_hdr hdr;
>> + u16 revision;
>> + u16 nr_entries;
>> + /* uefi_cfg_entries[] */
>
> Use a flex array
>
>> +} __packed;
>> +
>> +struct slr_uefi_cfg_entry {
>> + u16 pcr;
>> + u16 reserved;
>> + u64 cfg; /* address or value */
>> + u32 size;
>> + char evt_info[TPM_EVENT_INFO_LENGTH];
>> +} __packed;
>> +
>> +static inline void *slr_end_of_entrys(struct slr_table *table)
>
> typo 'entrys' ?
>
>> +{
>> + return (((void *)table) + table->size);
>
> You can drop two sets of parens here
>
>> +}
>> +
>> +static inline struct slr_entry_hdr *
>> +slr_next_entry(struct slr_table *table,
>> + struct slr_entry_hdr *curr)
>> +{
>> + struct slr_entry_hdr *next = (struct slr_entry_hdr *)
>> + ((u8 *)curr + curr->size);
>> +
>> + if ((void *)next >= slr_end_of_entrys(table))
>> + return NULL;
>> + if (next->tag == SLR_ENTRY_END)
>> + return NULL;
>> +
>> + return next;
>> +}
>> +
>> +static inline struct slr_entry_hdr *
>> +slr_next_entry_by_tag(struct slr_table *table,
>> + struct slr_entry_hdr *entry,
>> + u16 tag)
>> +{
>> + if (!entry) /* Start from the beginning */
>> + entry = (struct slr_entry_hdr *)(((u8 *)table) + sizeof(*table));
>> +
>> + for ( ; ; ) {
>> + if (entry->tag == tag)
>> + return entry;
>> +
>> + entry = slr_next_entry(table, entry);
>> + if (!entry)
>> + return NULL;
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +static inline int
>> +slr_add_entry(struct slr_table *table,
>> + struct slr_entry_hdr *entry)
>> +{
>> + struct slr_entry_hdr *end;
>> +
>> + if ((table->size + entry->size) > table->max_size)
>> + return -1;
>> +
>> + memcpy((u8 *)table + table->size - sizeof(*end), entry, entry->size);
>> + table->size += entry->size;
>> +
>> + end = (struct slr_entry_hdr *)((u8 *)table + table->size - sizeof(*end));
>> + end->tag = SLR_ENTRY_END;
>> + end->size = sizeof(*end);
>> +
>> + return 0;
>> +}
>> +
>> +static inline void
>> +slr_init_table(struct slr_table *slrt, u16 architecture, u32 max_size)
>> +{
>> + struct slr_entry_hdr *end;
>> +
>> + slrt->magic = SLR_TABLE_MAGIC;
>> + slrt->revision = SLR_TABLE_REVISION;
>> + slrt->architecture = architecture;
>> + slrt->size = sizeof(*slrt) + sizeof(*end);
>> + slrt->max_size = max_size;
>> + end = (struct slr_entry_hdr *)((u8 *)slrt + sizeof(*slrt));
>> + end->tag = SLR_ENTRY_END;
>> + end->size = sizeof(*end);
>> +}
>> +
>> +#endif /* !__ASSEMBLY */
>> +
>> +#endif /* _LINUX_SLR_TABLE_H */
>> --
>> 2.39.3
>>